1 from types import StringTypes
5 from PLC.Faults import *
6 from PLC.Parameter import Parameter
10 Representation of a row in a database table. To use, optionally
11 instantiate with a dict of values. Update as you would a
12 dict. Commit to the database with sync().
15 # Set this to the name of the table that stores the row.
18 # Set this to the name of the primary key of the table. It is
19 # assumed that the this key is a sequence if it is not set when
23 # Set this to the names of tables that reference this table's
27 # Set this to a dict of the valid fields of this object and their
28 # types. Not all fields (e.g., joined fields) may be updated via
32 def __init__(self, api, fields = {}):
33 dict.__init__(self, fields)
38 Validates values. Will validate a value with a custom function
39 if a function named 'validate_[key]' exists.
42 # Warn about mandatory fields
43 mandatory_fields = self.api.db.fields(self.table_name, notnull = True, hasdef = False)
44 for field in mandatory_fields:
45 if not self.has_key(field) or self[field] is None:
46 raise PLCInvalidArgument, field + " must be specified and cannot be unset in class %s"%self.__class__.__name__
48 # Validate values before committing
49 for key, value in self.iteritems():
50 if value is not None and hasattr(self, 'validate_' + key):
51 validate = getattr(self, 'validate_' + key)
52 self[key] = validate(value)
54 def separate_types(self, items):
56 Separate a list of different typed objects.
57 Return a list for each type (ints, strs and dicts)
60 if isinstance(items, (list, tuple, set)):
61 ints = filter(lambda x: isinstance(x, (int, long)), items)
62 strs = filter(lambda x: isinstance(x, StringTypes), items)
63 dicts = filter(lambda x: isinstance(x, dict), items)
64 return (ints, strs, dicts)
66 raise PLCInvalidArgument, "Can only separate list types"
69 def associate(self, *args):
71 Provides a means for high lvl api calls to associate objects
76 raise PLCInvalidArgumentCount, "auth, field, value must be specified"
77 elif hasattr(self, 'associate_' + args[1]):
78 associate = getattr(self, 'associate_'+args[1])
81 raise PLCInvalidArguemnt, "No such associate function associate_%s" % args[1]
83 def validate_timestamp(self, timestamp, check_future = False):
85 Validates the specified GMT timestamp string (must be in
86 %Y-%m-%d %H:%M:%S format) or number (seconds since UNIX epoch,
87 i.e., 1970-01-01 00:00:00 GMT). If check_future is True,
88 raises an exception if timestamp is not in the future. Returns
89 a GMT timestamp string.
92 time_format = "%Y-%m-%d %H:%M:%S"
94 if isinstance(timestamp, StringTypes):
95 # calendar.timegm() is the inverse of time.gmtime()
96 timestamp = calendar.timegm(time.strptime(timestamp, time_format))
98 # Human readable timestamp string
99 human = time.strftime(time_format, time.gmtime(timestamp))
101 if check_future and timestamp < time.time():
102 raise PLCInvalidArgument, "'%s' not in the future" % human
106 def add_object(self, classobj, join_table, columns = None):
108 Returns a function that can be used to associate this object
112 def add(self, obj, columns = None, commit = True):
114 Associate with the specified object.
117 # Various sanity checks
118 assert isinstance(self, Row)
119 assert self.primary_key in self
120 assert join_table in self.join_tables
121 assert isinstance(obj, classobj)
122 assert isinstance(obj, Row)
123 assert obj.primary_key in obj
124 assert join_table in obj.join_tables
126 # By default, just insert the primary keys of each object
127 # into the join table.
129 columns = {self.primary_key: self[self.primary_key],
130 obj.primary_key: obj[obj.primary_key]}
133 for name, value in columns.iteritems():
134 params.append(self.api.db.param(name, value))
136 self.api.db.do("INSERT INTO %s (%s) VALUES(%s)" % \
137 (join_table, ", ".join(columns), ", ".join(params)),
145 add_object = classmethod(add_object)
147 def remove_object(self, classobj, join_table):
149 Returns a function that can be used to disassociate this
153 def remove(self, obj, commit = True):
155 Disassociate from the specified object.
158 assert isinstance(self, Row)
159 assert self.primary_key in self
160 assert join_table in self.join_tables
161 assert isinstance(obj, classobj)
162 assert isinstance(obj, Row)
163 assert obj.primary_key in obj
164 assert join_table in obj.join_tables
166 self_id = self[self.primary_key]
167 obj_id = obj[obj.primary_key]
169 self.api.db.do("DELETE FROM %s WHERE %s = %s AND %s = %s" % \
171 self.primary_key, self.api.db.param('self_id', self_id),
172 obj.primary_key, self.api.db.param('obj_id', obj_id)),
180 remove_object = classmethod(remove_object)
182 def db_fields(self, obj = None):
184 Return only those fields that can be set or updated directly
185 (i.e., those fields that are in the primary table (table_name)
186 for this object, and are not marked as a read-only Parameter.
192 db_fields = self.api.db.fields(self.table_name)
193 return dict(filter(lambda (key, value): \
194 key in db_fields and \
195 (key not in self.fields or \
196 not isinstance(self.fields[key], Parameter) or \
197 not self.fields[key].ro),
205 # Filter out fields that cannot be set or updated directly
206 # (and thus would not affect equality for the purposes of
207 # deciding if we should sync() or not).
209 y = self.db_fields(y)
210 return dict.__eq__(x, y)
212 def sync(self, commit = True, insert = None):
214 Flush changes back to the database.
217 # Validate all specified fields
220 # Filter out fields that cannot be set or updated directly
221 db_fields = self.db_fields()
223 # Parameterize for safety
224 keys = db_fields.keys()
225 values = [self.api.db.param(key, value) for (key, value) in db_fields.items()]
227 # If the primary key (usually an auto-incrementing serial
228 # identifier) has not been specified, or the primary key is the
229 # only field in the table, or insert has been forced.
230 if not self.has_key(self.primary_key) or \
231 keys == [self.primary_key] or \
234 sql = "INSERT INTO %s (%s) VALUES (%s)" % \
235 (self.table_name, ", ".join(keys), ", ".join(values))
237 # Update existing row
238 columns = ["%s = %s" % (key, value) for (key, value) in zip(keys, values)]
239 sql = "UPDATE %s SET " % self.table_name + \
240 ", ".join(columns) + \
243 self.api.db.param(self.primary_key, self[self.primary_key]))
245 self.api.db.do(sql, db_fields)
247 if not self.has_key(self.primary_key):
248 self[self.primary_key] = self.api.db.last_insert_id(self.table_name, self.primary_key)
253 def delete(self, commit = True):
255 Delete row from its primary table, and from any tables that
259 assert self.primary_key in self
261 for table in self.join_tables + [self.table_name]:
262 if isinstance(table, tuple):
266 key = self.primary_key
268 sql = "DELETE FROM %s WHERE %s = %s" % \
270 self.api.db.param(self.primary_key, self[self.primary_key]))
272 self.api.db.do(sql, self)
279 Representation of row(s) in a database table.
282 def __init__(self, api, classobj, columns = None):
284 self.classobj = classobj
288 columns = classobj.fields
290 columns = filter(lambda x: x in classobj.fields, columns)
292 raise PLCInvalidArgument, "No valid return fields specified"
294 self.columns = columns
296 def sync(self, commit = True):
298 Flush changes back to the database.
304 def selectall(self, sql, params = None):
306 Given a list of rows from the database, fill ourselves with
310 for row in self.api.db.selectall(sql, params):
311 obj = self.classobj(self.api, row)
314 def dict(self, key_field = None):
316 Return ourself as a dict keyed on key_field.
319 if key_field is None:
320 key_field = self.classobj.primary_key
322 return dict([(obj[key_field], obj) for obj in self])